Align key for a TOC/COT-type liquid crystal display device and method of fabricating the same

ABSTRACT

An align key device for a TOC/COT-type liquid crystal display (LCD) device having first and second substrates facing each other with a predetermined space therebetween, and a liquid crystal material layer disposed between the first and second substrates, includes a first align key formed on a non-active area of the first substrate, and a second align key formed on the second substrate facing and aligning with the first align key, the second align key being formed of silver paste.

[0001] This application claims the benefit of Korean Patent ApplicationNo. 2001-84258 filed in Korea on Dec. 24, 2001, which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a liquid crystal display (LCD)device and a method of fabricating the same, and more particularly, toan align key for thin film transistor on a color filter (TOC)-type orcolor filter on thin film transistor (COT)-type LCD device and method offabricating the same.

[0004] 2. Discussion of the Related Art

[0005] As the information age rapidly evolves, a necessity for a flatpanel display, which has advantages such as being thin, beinglightweight, and having lower power consumption, has been increased.Liquid crystal display (LCD) devices are actively applied to notebookcomputers and desktop monitors, because of their superiority inresolution, display of color images and displaying quality. For example,active matrix liquid crystal display (AMLCD) devices, in which the thinfilm transistors and the pixel electrodes are arranged in the form of amatrix, are widely used because of their high resolution and superiorityin displaying moving images.

[0006] In general, an LCD device is fabricated through an arraysubstrate forming process, a color filter substrate forming process, anda liquid crystal cell forming process. A thin film transistor and apixel electrode are formed in the array substrate forming process, and acolor filter and a common electrode are formed in the color filtersubstrate forming process. Liquid crystal material is then injectedbetween the array and color filter substrates in the liquid crystal cellforming process. The liquid crystal cell forming process commonlycomprises an alignment layer forming process, a cell gap formingprocess, assembling process, a cell cutting process, and a liquidcrystal injection process.

[0007]FIG. 1 is a cross-sectional view of a liquid crystal display (LCD)device according to the related art. In FIG. 1, an LCD device includesupper and lower substrates 10 and 30 spaced apart from each other with apredetermined space therebetween, and a liquid crystal material layer 50disposed between the upper and lower substrates 10 and 30. A gateelectrode 32 and a gate insulating layer 34 are sequentially formed on atransparent substrate 1 of the lower substrate 30. In addition, asemiconductor layer 36, which has an active layer 36 a and an ohmiccontact layer 36 b, is formed over the gate electrode 32. Source anddrain electrodes 38 and 40 are then formed spaced apart from each otheron the semiconductor layer 36. A channel ch exposing a portion of theactive layer 36 a is formed between the source and drain electrodes 38and 40. The gate electrode 32, the semiconductor layer 36, the channelch, and the source and drain electrodes 38 and 40 form a thin filmtransistor T.

[0008] Furthermore, a gate line (not shown) is formed in a firstdirection connected to the gate electrode 32, and a data line (notshown) is formed in a second direction connected to the source electrode38, such that the data line is perpendicular to the gate line. The dataline defines a pixel region P by crossing the gate line. In addition, apassivation layer 42, which has a drain contact hole 44, is formed onthe thin film transistor T. A pixel electrode 48, which contacts thedrain electrode 40 through the drain contact hole 44, is formed in thepixel region P. A color filter 14, which filters light of a particularwavelength range, is formed beneath a transparent substrate 1 of theupper substrate 10.

[0009] Moreover, a black matrix 12 is formed in a boundary between eachpixel region P to prevent a light leakage in the thin film transistor Tregion and an incoming of light into the thin film transistor T. Acommon electrode 16 is formed beneath the color filter 14 and the blackmatrix 12 to apply voltage to the liquid crystal layer 50. In addition,a seal pattern 52 is formed along edges of the first and secondsubstrates 10 and 30 to prevent leakage of the liquid crystal betweenthe first and second substrates 10 and 30. The seal pattern 52 is formedbefore the assembling process of the first and second substrates 10 and30. Furthermore, the seal pattern 52 keeps a constant cell gap distance,thereby making the liquid crystal material injection process easier andpreventing any injected liquid crystal material from leaking.

[0010] The LCD device further has alignment layers (not shown) betweenthe upper substrate 10 and the liquid crystal layer 50, and between thelower substrate 30 and the liquid crystal layer 50. An aligning errormargin for the assembling process of the first and second substrates 10and 30 is commonly less than a few micrometers. However, if the upperand lower substrates 10 and 30 are aligned and attached with an aligningmargin larger than the error margin of a few micrometers, displayquality of the liquid crystal display deteriorates due to a lightleakage during operation of the liquid crystal cell.

[0011] Furthermore, as the liquid crystal display (LCD) device becomesmore and more integrated to display high quality images, space betweenelements becomes narrower. Accordingly, if there is a minor assemblingerror and thus an element is disposed in a position other than aninitially designed position, a color reproduction quality isdeteriorated.

[0012] Moreover, an LCD device, which has a structure wherein the colorfilter and the thin film transistor are formed in separate substrates,has the following disadvantages. First, assembling accuracy and apertureratio may be decreased due to the misalignment of the array and colorfilter substrates. Second, if the assembling margin is reduced toincrease the aperture ratio, light leakage phenomenon may occur. Third,because the color filter substrate and the array substrate should beformed in separate processes, it takes a long time to manufacture aliquid crystal panel. Thus, a TOC/COT-type LCD device has beensuggested, wherein the thin film transistor and the color filter areformed in the same substrate.

[0013]FIG. 2 is a cross-sectional view of a TOC/COT-type LCD deviceaccording to the related art. In FIG. 2, a liquid crystal layer 90 isdisposed between upper and lower substrates 60 and 70. A color filter 72is formed on a transparent substrate 1 of the lower substrate 70. Inaddition, a flattening layer 74 is formed in each boundary for eachcolor of the color filter 72 and on the color filter 72. An arrayelement I is formed on the flattening layer 74, wherein the arrayelement I has a thin film transistor T and a pixel electrode 78.Furthermore, a black matrix 62 is formed beneath the upper substrate 60corresponding to the thin film transistor T to prevent light fromflowing into the thin film transistor T. A common electrode 64 is formedbeneath the black matrix 62. Because the array element I is disposedover the color filter 72, the color filter 72 can be divided intosections for each color. Light leakage can be prevented by the electrolines of the array element I that is formed of opaque material.

[0014]FIG. 3A is a plan view of an upper substrate for a TOC/COT-typeLCD device according to the related art, and FIG. 3B is a magnified viewof an area IIIA of FIG. 3A. In FIG. 3A, the upper substrate 60 has anactive area IIA and a non-active area IIB. The common electrode 64 isextended to a boundary region of the active area IIA and the non-activearea IIB. The black matrix 62 is formed in each pixel region of theactive area IIA corresponding to the thin film transistor T (not shown)of the lower substrate (not shown). Align keys 94 are formed with samematerial as the black matrix in each corner of the non-active area IIB.A seal pattern 92 having an injection hole 91 is formed along edges ofthe common electrode 64 to assemble the upper and lower substrates 60and 70 and form a cell gap. In FIG. 3B, the seal pattern 92 has aconcave portion IIIB that exposes a portion of the common electrode 64.A silver dot 93, which is formed with silver (Ag) paste, is formed onthe common electrode 64 corresponding to the concave portion IIIB of theseal pattern 92. The silver dot 93 serves to connect the upper and lowersubstrates 60 and 70 electrically and generally is formed by a pointdotting method using a dispenser.

[0015] As stated above, the manufacturing process for the uppersubstrate 60 of the TOC/COT-type LCD device is complex because theprocess includes many processes, such as forming the common electrode64, forming the black matrix 62 and the align key 94 with organicmaterial or metal material, forming the seal pattern 92 and forming thesilver dot 93. If the black matrix 62 is formed on the upper substrate60, an assembling accuracy of the upper and lower substrates 60 and 70may be decreased owing to an aligning margin with the thin filmtransistor T on the lower substrate 70. If the aligning margin isdecreased, light leakage current may occur. Besides, because the blackmatrix 62 and the align key is formed by a photolithographic maskingprocess that comprises a coating process, a light exposure process, adeveloping process, and an etching process, an accuracy of the align key94, which is usually formed to have scores of micrometers (μm) pattern,is decreased and production yield may be low.

SUMMARY OF THE INVENTION

[0016] Accordingly, the present invention is directed to an align key ofa TOC/COT-type LCD device and a method of fabricating the same thatsubstantially obviates one or more of problems due to limitations anddisadvantages of the related art.

[0017] An object of the present invention is to provide TOC/COT-type LCDdevices in which an align key for an upper substrate is formed of silverpaste by a printing device such as an inkjet device.

[0018] Another object of the present invention is to provideTOC/COT-type LCD devices in which an align key for an upper substrate isformed of organic polymer by screen-print method.

[0019] Another object of the present invention is to provide a method offabricating TOC/COT-type LCD devices in which an align key for an uppersubstrate is formed of silver paste by a printing device such as aninkjet device.

[0020] Another object of the present invention is to provide a method offabricating TOC/COT-type LCD devices in which an align key for an uppersubstrate is formed of organic polymer by screen-print method.

[0021] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objectives and other advantages of the invention will be realizedand attained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

[0022] To achieve these and other advantages and in accordance with thepurpose of the present invention, as embodied and broadly described, analign key device for a TOC/COT-type liquid crystal display (LCD) devicehaving first and second substrates facing each other with apredetermined space therebetween, and a liquid crystal material layerdisposed between the first and second substrates, includes a first alignkey formed on a non-active area of the first substrate, and a secondalign key formed on the second substrate facing and aligning with thefirst align key, the second align key being formed of silver paste.

[0023] In another aspect, a TOC/COT-type liquid crystal display (LCD)device includes a first substrate having an active area and a non-activearea, wherein a thin film transistor, a pixel electrode and a colorfilter are formed thereon, a second substrate having a common electrodeformed thereon, wherein the first and second substrates are facing eachother at a predetermined space therebetween, a liquid crystal materiallayer disposed between the first and second substrates, a first alignkey formed on the non-active area of the first substrate, and a secondalign key formed on the second substrate facing and aligning with thefirst align key, the second align key being formed of silver paste.

[0024] In another aspect, an align key device for a TOC/COT-type liquidcrystal display (LCD) device having first and second substrates facingeach other with a predetermined space therebetween, and a liquid crystalmaterial layer disposed between the first and second substrates,includes a first align key on a non-active area of the first substrate,and a second align key on the second substrate facing and aligning withthe first align key, the second align key being formed of an organicpolymer by a screen-print method.

[0025] In another aspect, a TOC/COT-type liquid crystal display (LCD)device, includes a first substrate having an active area, a non-activearea, a thin film transistor, a pixel electrode and a color filterformed thereon, a second substrate having a common electrode formedthereon, wherein the first and second substrates face each other at apredetermined space therebetween, a liquid crystal layer disposedbetween the first and second substrates, a seal pattern in a boundaryregion of the active area and the non-active area, a first align key onthe non-active area of the first substrate, and a second align key onthe second substrate facing and aligning with the first align key, thesecond align key being formed of an organic polymer by a screen-printmethod.

[0026] In another aspect, a method of fabricating a TOC/COT-type liquidcrystal display (LCD) device, includes forming a first substrate havingan active area and a non-active area, wherein a thin film transistor, apixel electrode, a color filter and a first align key are formed thereonwithin the non-active area, forming a second substrate having a commonelectrode formed thereon, arranging the second substrate facing thefirst substrate with a predetermined space therebetween, cleaning thefirst and second substrates, forming a second align key on thenon-active area of the second substrate with silver paste, formingalignment layers respectively on the first and second substrates usingthe first and second align keys as a base, forming a seal pattern on oneof the first and second substrates, dispensing spacers between the firstand second substrates, assembling the first and second substrates usingthe first and second align keys as a base, cutting the assembledsubstrates into an individual liquid crystal cell, injecting liquidcrystal material into the liquid crystal cell, and sealing the liquidcrystal cell.

[0027] In another aspect, A method of fabricating a TOC/COT-type liquidcrystal display (LCD) device, includes forming a first substrate havingan active area and a non-active area, wherein a thin film transistor, apixel electrode, a color filter and a first align key formed within thenon-active area, forming a second substrate having a common electrode,arranging the second substrate facing the first substrate with apredetermined space therebetween, cleaning the first and secondsubstrates, forming a second align key on the non-active area of thesecond substrate with an organic polymer by a screen mask, formingalignment layers respectively on the first and second substrates usingthe first and second align keys as a base, forming a seal pattern on thesecond substrate, dispensing spacers between the first and secondsubstrates, assembling the first and second substrates using the firstand second align keys as a base, cutting the assembled substrates intoan individual liquid crystal cell, injecting liquid crystal materialinto the liquid crystal cell, and sealing the liquid crystal cell.

[0028] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciples of the invention. In the drawings:

[0030]FIG. 1 is a cross-sectional view of a liquid crystal display (LCD)device according to the related art;

[0031]FIG. 2 is a cross-sectional view of a TOC/COT-type LCD deviceaccording to the related art;

[0032]FIG. 3A is a plan view of an upper substrate for a TOC/COT-typeLCD device according to the related art;

[0033]FIG. 3B is a magnified view of an area IIA of FIG. 3A;

[0034]FIG. 4 is a cross-sectional view of an exemplary TOC/COT-type LCDdevice according to the present invention;

[0035]FIG. 5 is a flow chart illustrating an exemplary method offabricating a liquid crystal cell for TOC/COT-type LCD devices accordingto the present invention;

[0036]FIG. 6 is a schematic diagram illustrating an exemplary method offabricating an align key using an inkjet device according to the presentinvention;

[0037]FIG. 7 is a flow chart illustrating another exemplary method offabricating a liquid crystal cell for TOC/COT-type LCD devices accordingto the present invention;

[0038]FIG. 8 is a schematic diagram illustrating another exemplarymethod of fabricating align key using a screen-print method according tothe present invention; and

[0039]FIG. 9 is a flow chart illustrating another exemplary method offabricating a liquid crystal cell for TOC/COT-type LCD devices accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings.

[0041]FIG. 4 is a cross-sectional view of an exemplary TOC/COT-type LCDdevice according to the present invention. In FIG. 4, an LCD device mayinclude upper and lower substrates 110 and 130 having an active area IVaand a non-active area IVb, and spaced facing each other with apredetermined space therebetween, and a liquid crystal material layer150 disposed between the upper and lower substrates 110 and 130. Acommon electrode 114 may be formed on the upper substrate 110, and acolor filter 132 may be formed in the active area IVa on a transparentsubstrate 100 of the lower substrate 130. Also, a flattening layer 134may be formed between each boundary of each pixel of the color filter132 and on the color filter 132 to form a uniform surface on the lowersubstrate 130. A thin film transistor T having a gate electrode 136, asemiconductor layer 138, source and drain electrodes 140 and 142 may beformed on the flattening layer 134. A passivation layer 146 having adrain contact hole 144 may be formed on the thin film transistor T, anda black matrix 112 may be formed on the passivation layer 146corresponding to the thin film transistor T.

[0042] In addition, a pixel electrode 148, which contacts the drainelectrode 142 through the drain contact hole 144, may be formed oftransparent conductive metal material on a pixel region P. The pixelelectrode 148 and the color filter 132 may extend to an adjacent pixelregion P to improve an aperture ratio. Furthermore, the pixel electrode148 and the color filter 132 may not be confined to the above-mentionedstructure. The color filter 132 may be formed by a dye method, anelectrodeposition method, a pigment dispersion method or a print method.The flattening layer 134 and the passivation layer 146 may be formed oforganic or inorganic material, such as benzocyclobutene (BCB) or acrylicresin that is superior in a flattening property. The black matrix 112and the thin film transistor T may be formed in a same substrate. Forexample, the black matrix 112 may be formed on the passivation layer 146before the formation of the pixel electrode 148. The black matrix 112may be made of a black resin material.

[0043] Furthermore, upper and lower align keys 152 and 154 may berespectively formed on an inner surface of the upper and lowersubstrates 110 and 130 in the non-active area IVb. The upper align key152 may correspond to the lower align key 154. Also, the lower align key154 may be formed during the formation of array elements and the upperalign key 152 by a printing apparatus using silver (Ag) paste or screenmask apparatus using organic polymer. The printing apparatus may includean inkjet apparatus of a roller, and the screen mask apparatus mayinclude a high-resolution mask apparatus. The silver paste may be formedby depositing a mixture of silver powder, inorganic bonding agent andorganic bonding agent on ceramic and then sintering it. In addition, theorganic polymer may be formed using one of sealant, epoxy resin, acrylresin and photoresist. Moreover, the upper align key 152 may be formedwith silver paste to serve as a silver dot (not shown).

[0044] Accordingly, the black matrix 112 may be formed in the lowersubstrate 130 on which the thin film transistor T is formed. Inaddition, the upper align key 152 may be formed on the upper substrate110 with same material as the silver dot or the seal pattern withoutadditional photolithographic masking process, thereby reducing analignment margin of the upper and lower substrates 110 and 130, andsimplifying a process of fabricating the upper substrate 110.

[0045]FIG. 5 is a flow chart illustrating an exemplary method offabricating a liquid crystal cell for TOC/COT-type LCD devices accordingto the present invention. In FIG. 5, ST1, a first substrate having afirst align key, a color filter and all array elements formed thereon,and a second substrate having only a common electrode formed thereon maybe cleaned to remove impurities on the substrates before forming analignment layer on the substrates. In ST2, a second align key may beformed on the second substrate by a printing apparatus using silverpaste. For example, the printing apparatus may include an inkjetapparatus or a roller.

[0046] In ST3, an alignment layer may be formed on the first and secondsubstrates using the second align key as an alignment layer key. Thealignment layer forming method may include printing the alignment layer,curing the alignment layer and rubbing the alignment layer. For example,the alignment layer may be formed of polymer thin film and may beprinted on the first and second substrates. The printed alignment layermay be then cured as it passes through a preliminary drier and then anoven. Subsequently, a surface of the cured alignment layer may be thenrubbed a certain direction with a rubbing fabric to align liquid crystalmolecules in the rubbing direction.

[0047] In ST4, a silver dot may be formed with same material as thesecond align key on the second substrate. For example, the silver dotmay be formed in an outer edge of the common electrode and serve toconnect the first and second substrates electrically. The silver dot maybe formed by the inkjet method as the second alignment key. Accordingly,because the second align key may be formed using the same material andapparatus as those of the silver dot, a production cost can be decreasedand an assembling accuracy can be improved.

[0048] In ST5, a seal pattern may be formed, and spacers may bedispensed on the substrate. The seal pattern may form a gap for liquidcrystal material injection and prevent the injected liquid crystalmaterial from leaking. The seal pattern may be formed with a sealantmaterial, such as thermosetting resin having glass fiber, by ascreen-printing method. The spacers may keep a uniform gap between thefirst and second substrate, such that the LCD device has a uniformdensity. In addition, the spacers may be formed by a wet dispensingmethod in which a mixture of the spacers and alcohol is sprayed, or adry dispensing method in which only the spacers are dispensed.

[0049] ST6, the first and second substrates may be assembled to beaffixed to each other using the first and second align keys as anassembling key. The alignment degree of the first and second substratesmay depend on a margin that is decided when the substrates are designed.For example, the aligning margin is usually about less than a fewmicrometers (μm). In ST7, the assembled substrates may be cut into aplurality of individual liquid crystal cells in a cutting process. Thecutting process may include scribing the substrates to form cuttinglines, and breaking the substrates along the scribed lines to form theindividual liquid crystal cells. For example, a diamond pen or a cuttingwheel formed of tungsten carbide may be used for scribing.

[0050] In ST8, a liquid crystal material may be injected into each ofthe individual liquid crystal cells through an injection hole. Sinceeach of the individual liquid crystal cells has a gap ratio of only afew micrometers per hundreds of square centimeters (cm²) in itssubstrate surface area, a vacuum injection process utilizing a pressuredifference may be used. After the liquid crystal injection process, theinjection hole may be sealed with an end seal. Thereafter, the liquidcrystal cell, which underwent all of the above steps, may be inspectedand then a polarizer may be formed on an outer side of the liquidcrystal cell. Accordingly, the LCD device may be completed by attachinga driving circuit to the liquid crystal cell.

[0051]FIG. 6 is a schematic diagram illustrating an exemplary method offabricating an align key using an inkjet device according to the presentinvention. In FIG. 6, an inkjet device 160 may include an inkjet head160 a and a nozzle 160 b. For example, the inkjet head 160 a may containsilver paste 162, and the inkjet head 160 a may jet the silver pastethrough the nozzle 160 b. An align key 164 may be formed by disposingthe inkjet device 160 over a substrate 166 and then jetting the silverpaste into the substrate 166 through the nozzle 160 b. The inkjet head160 a further comprises an oscillator (not shown) generating vibrationsat a constant frequency, and an oscillating plate (not shown) having aconstant frequency to control an amount of silver paste being jettedthrough the nozzle 160 b. Accordingly, a minute pattern of the align keyin a range of a few micrometers (μm) may be formed.

[0052]FIG. 7 is a flow chart illustrating another exemplary method offabricating a liquid crystal cell for TOC/COT-type LCD devices accordingto the present invention. In FIG. 7, ST11, a first substrate having afirst align key, a color filter, and other array elements formedthereon, and a second substrate having a common electrode formed thereinmay be cleaned. In ST22, a second align key having a combined use for analign key and a silver dot may be formed on the second substrate in aposition where the silver dot is to be formed. Accordingly, it isimportant that the first align key should be formed in a positioncorresponding to the second align key.

[0053] In ST33, an alignment layer may be formed. The alignment layermay be formed using a low temperature alignment layer forming process.In addition, in ST44, a seal pattern may be formed and spacers may bedispensed. In ST55, the first and second substrates may be assembled tobe affixed to each other. In ST66, the assembled substrates may be cutinto a plurality of individual liquid crystal cells. Then, in ST77, aliquid crystal material may be injected into the individual liquidcrystal cell through an injection hole, such that the injection hole maybe sealed after the injection of the liquid crystal material. Then, theliquid crystal cell may undergo an inspection process and then apolarizer may be formed on an outer surface of the liquid crystal cell.Accordingly, an LCD device may be completed by attaching a drivingcircuit to the liquid crystal cell. Furthermore, since the second alignkey may serve as the silver dot, an additional process for forming thesilver dot is unnecessary.

[0054]FIG. 8 is a schematic diagram illustrating another exemplarymethod of fabricating align key using a screen-print method according tothe present invention. In FIG. 8, a screen-print device 210 may includea screen mask 200 on which a certain pattern 204 is formed and asqueegee 202, such the squeegee 202 may be drawn across a surface of thescreen mask 200 to facilitate printing of the pattern 204. An align key208 may be formed on a substrate 206. The align key 208 may be used forprinting an alignment layer, printing a seal pattern or assembling thesubstrates. The screen mask 200 may have a higher resolution than a maskthat is generally used for a seal pattern. For example, the screen mask200 may have meshes density between about 350 and about 500 mesh, and athickness of an emulsion for the mask be between about 10 μm and about25 μm. The align key 208 may be formed of thermosetting resin thatcontains glass fiber and is used for the seal pattern. Alternatively,the align key 208 may be formed one of epoxy resin, acryl resin andphotoresist when another screen mask, which is different from that ofthe seal pattern, is used. If the align key is formed by thescreen-print method, the align key may be formed with same material andapparatus as those of the seal pattern, thereby simplifying thefabricating process.

[0055]FIG. 9 is a flow chart illustrating another exemplary method offabricating a liquid crystal cell for TOC/COT-type LCD devices accordingto the present invention. In FIG. 9, ST111, a first substrate having afirst align key, a color filter and other array elements formed thereonand a second substrate having a common electrode formed thereon may becleaned. In ST222, a second align key may be formed on one of the firstand second substrates using the screen mask. The second align key may beformed of a sealant material used for a seal pattern or an organicpolymer material that is suitable for a screen-print method. Inaddition, the screen mask may have a high resolution. In ST333, analignment layer may be formed on the first and second substrates. InST444, a seal pattern may be formed and spacers may be dispensed betweenthe first and second substrates. In ST555, the first and secondsubstrates may be assembled to be affixed to each other. In ST666, theassembled substrates may be cut into a plurality of individual liquidcrystal cells. In ST777, a liquid crystal material may be injected intothe individual liquid crystal cells through an injection hole, such thatthe injection hole may be sealed after the injection. Thereafter, theliquid crystal cells may undergo an inspection process (not shown), anda polarizer may be formed on an outer surface of each of the liquidcrystal cells. Furthermore, a driving circuit may be attached to each ofthe individual liquid crystal cell to form a LCD device.

[0056] Although the aforementioned embodiments describe a TOC-type LCDdevice, a COT-type LCD device may be similarly formed, except that thecolor filter is formed over the thin film transistor.

[0057] The aforementioned embodiments have the following advantages.First, a method of fabricating a second substrate may be simplified.Second, an accuracy of an align key, which is a minute pattern, can beimproved. Third, cost for an investment of an apparatus and material canbe reduced and a production yield can be increased by omitting aphotolithographic mask process during forming the second substrate.

[0058] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the align key for aTOC/COT-type liquid crystal display device and the method of fabricatingthe same of the present invention without departing from the spirit orscope of the invention. Thus, it is intended that the present inventioncover the modifications and variations of this invention provided theycome within the scope of the appended claims and their equivalents.

What is claimed is:
 1. An align key device for a TOC/COT-type liquidcrystal display (LCD) device having first and second substrates facingeach other with a predetermined space therebetween, and a liquid crystalmaterial layer disposed between the first and second substrates,comprising: a first align key formed on a non-active area of the firstsubstrate; and a second align key formed on the second substrate facingand aligning with the first align key, the second align key being formedof silver paste.
 2. The device according to claim 1, wherein the secondalign key is formed by an inkjet device.
 3. A TOC/COT-type liquidcrystal display (LCD) device, comprising: a first substrate having anactive area and a non-active area, wherein a thin film transistor, apixel electrode and a color filter are formed thereon; a secondsubstrate having a common electrode formed thereon, wherein the firstand second substrates are facing each other at a predetermined spacetherebetween; a liquid crystal material layer disposed between the firstand second substrates; a first align key formed on the non-active areaof the first substrate; and a second align key formed on the secondsubstrate facing and aligning with the first align key, the second alignkey being formed of silver paste.
 4. The device according to claim 3,further comprising a seal pattern formed in a boundary region of theactive area and the non-active area, wherein the seal pattern includes aplurality of concave portions that expose partial edge portions of thecommon electrode.
 5. The device according to claim 4, further comprisinga plurality of silver dots, which are formed using a same material asthe second align key and formed on the common electrode adjacent to theconcave portions.
 6. The device according to claim 5, wherein the secondalign key and the silver dot are formed by an inkjet device.
 7. Thedevice according to claim 3, wherein the second align key may be formedon the common electrode adjacent to the concave portions, the secondalign key having a combined use as an align key and a silver dot.
 8. Thedevice according to claim 3, further comprising a passivation layer onthe thin film transistor and a black matrix on the passivation layercorresponding to the thin film transistor.
 9. The device according toclaim 8, wherein the black matrix includes a black resin material. 10.An align key device for a TOC/COT-type liquid crystal display (LCD)device having first and second, substrates facing each other with apredetermined space therebetween, and a liquid crystal material layerdisposed between the first and second substrates, comprising: a firstalign key on a non-active area of the first substrate; and a secondalign key on the second substrate facing and aligning with the firstalign key, the second align key being formed of an organic polymer by ascreen-print method.
 11. The device according to claim 10, wherein theorganic polymer includes one of epoxy resin, acryl resin andphotoresist.
 12. A TOC/COT-type liquid crystal display (LCD) device,comprising; a first substrate having an active area, a non-active area,a thin film transistor, a pixel electrode and a color filter formedthereon; a second substrate having a common electrode formed thereon,wherein the first and second substrates face each other at apredetermined space therebetween; a liquid crystal layer disposedbetween the first and second substrates; a seal pattern in a boundaryregion of the active area and the non-active area; a first align key onthe non-active area of the first substrate; and a second align key onthe second substrate facing and aligning with the first align key, thesecond align key being formed of an organic polymer by a screen-printmethod.
 13. The device according to claim 12, wherein the seal patternis formed of thermosetting resin that contains glass fiber and thesecond align key is formed of a same material as the seal pattern. 14.The device according to claim 12, wherein the organic polymer includesone of epoxy resin, acryl resin and photoresist.
 15. The deviceaccording to claim 12, further comprising a passivation layer on thethin film transistor and a black matrix on the passivation layercorresponding to the thin film transistor.
 16. The device according toclaim 15, wherein the black matrix includes a black resin material. 17.A method of fabricating a TOC/COT-type liquid crystal display (LCD)device, comprising the steps of: forming a first substrate having anactive area and a non-active area, wherein a thin film transistor, apixel electrode, a color filter and a first align key are formed thereonwithin the non-active area; forming a second substrate having a commonelectrode formed thereon; arranging the second substrate facing thefirst substrate with a predetermined space therebetween; cleaning thefirst and second substrates; forming a second align key on thenon-active area of the second substrate with silver paste; formingalignment layers respectively on the first and second substrates usingthe first and second align keys as a base; forming a seal pattern on oneof the first and second substrates; dispensing spacers between the firstand second substrates; assembling the first and second substrates usingthe first and second align keys as a base; cutting the assembledsubstrates into an individual liquid crystal cell; injecting liquidcrystal material into the liquid crystal cell; and sealing the liquidcrystal cell.
 18. The method according to claim 17, wherein the sealpattern is in a boundary region of the active area and the non-activearea and has a plurality of concave portions that expose partial edgeportions of the common electrode.
 19. The method according to claim 18,further comprising a step of forming a plurality of silver dots on thecommon electrode adjacent to the concave portions with same material asthe second align key before forming the seal pattern and dispensingspacers and after forming the alignment layer.
 20. The method accordingto claim 18, wherein the second align key is formed by spraying silverpaste onto the second substrate using an inkjet device.
 21. A method offabricating a TOC/COT-type liquid crystal display (LCD) device,comprising the steps of: forming a first substrate having an active areaand a non-active area, wherein a thin film transistor, a pixelelectrode, a color filter and a first align key formed within thenon-active area; forming a second substrate having a common electrode;arranging the second substrate facing the first substrate with apredetermined space therebetween; cleaning the first and secondsubstrates; forming a second align key on the non-active area of thesecond substrate with an organic polymer by a screen mask; formingalignment layers respectively on the first and second substrates usingthe first and second align keys as a base; forming a seal pattern on thesecond substrate; dispensing spacers between the first and secondsubstrates; assembling the first and second substrates using the firstand second align keys as a base; cutting the assembled substrates intoan individual liquid crystal cell; injecting liquid crystal materialinto the liquid crystal cell; and sealing the liquid crystal cell. 22.The method according to claim 21, wherein the seal pattern is formed ofsealant by the screen mask and the second align key is formed of samematerial as the seal pattern by a same device as that of the sealpattern.
 23. The method according to claim 21, wherein the organicpolymer includes one of epoxy resin, acryl resin and photoresist. 24.The method according to claim 21, wherein a screen of the screen maskhas meshes density between about 350 and about 500 mesh.
 25. The methodaccording to claim 24, wherein a thickness of an emulsion for the screenmask is between about 10 μm and about 25 μm.